1. Field of the Invention
The subject invention relates to a method of allowing access to an electronic device disposed in a working space by a user having a remote device in proximity to the electronic device.
2. Description of the Related Art
The related art provides various methods of determining the location of a remote device within a working space. The remote device includes a transmitter for emitting a radio frequency (RF) signal and a plurality of receivers positioned about an area for detecting the RF signals. U.S. Pat. No. 6,034,622 discloses receivers having internal clocks that must be synchronized and that detect RF signals. When the RF signals are detected, a time-of-arrival is detected at each of the receivers based upon the synchronized internal clocks. The internal clocks at each of the receivers are calibrated so that any time differences among them can be effectively zeroed out. The synchronization of these internal clocks is time consuming and is disadvantageous to allowing access to multiple electronic devices. Yet another method is disclosed in U.S. Pat. No. 6,556,942. The method utilizes short-range spread spectrum radiolocation techniques to determine the location of an object within a working space. However, the method requires the remote device to possess a fully synchronous architecture including an oscillator and a clock that is to be synchronized with the receivers.
U.S. Pat. No. Re. 36,791 discloses an object location system for use in multi-path environments. Multi-path is understood by those skilled in the art to include the transmission of an RF signal that does not take the shortest route to the receiver. In other words, the RF signal may be reflected off an object in the path to the receiver and then eventually reach the receiver or the RF signal may be transmitted through walls or the like. Multi-path issues result in inaccurate measurements of the distance between the remote device and the receiver. The '791 patent overcomes the multi-path issues by using multiple receivers that measure a time-of-arrival of the RF signals. However, each of the receivers includes internal clocks that must be synchronized. The synchronization occurs by a system processor coupled to the receivers by a network that generates a synchronization clock and transmits a signal to the receivers to synchronize to the clock. Such a system is time consuming and does not provide reliable distance measurements sufficient to allow a user access to electronic devices.
The related art is characterized by one or more inadequacies, such as, but not limited to, requiring the synchronization to determine the position of the remote device. During the synchronization of the devices, an error is incorporated that the synchronization nulls out during each synchronization. This step of removing and nulling the error is time consuming and does not provide sufficiently reliable measurements for enabling and disabling electronic devices.